Lightbar flew off while driving on highway!!

[2000prerunner]

I have been running off road lights on my vehicles for the last 25 years. Halogen , HIDs , LED bars and everything in between. never would I even consider mounting an off-road accessory light with adhesive. Bolt to bracket only . Not only is this incredibly strong, but it permits adjustability. Having the ability to aim your lights is fundamental. I even have an actuator on one of my trucks that help aim the light from inside. I love Tesla. But you can tell there’s a bunch of Dingus nerds that designed that OEM light bar . Booksmart type thinking. With zero real world practical off-road experience. It shows.
(this applies to that frail ass upper control arm, and the overall aluminum unibody chassis too. that simply doesn’t make a whole lot of sense for hard off-road use). Whatever. The still love the CT

My advice, go for an aftermarket LED light bar that uses brackets and bolts.

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[Diveflyfish]

Yeah, adhesive is dumb for cant rails and even more dumb for the lightbar. I wonder how many psi of force Is applied to that thing at highway speeds…..clearly a lot!

Adhesive is not dumb. The key is appreciation for coefficient of thermal expansion, ideal surface prep and realization of the incredible molecular level adhesion. Some materials you cannot bolt, rivet, etc, so also the potential benefit of vibration modulation etc.

 

[mongo]

Also, I wonder what material like rain-X or other superhydrophobic chemicals the windshield of those CB that lost the light? Perhaps an unseen alteration to the glass affected the bond. The only way the SC could ensure adequate surface prep is to know exactly what chemicals were used on the glass. To be sure appreciating what bonding agents require to work with extreme thermocycling is critical

It separated from the light bar, not the glass. Tesla added a bunch of notes to the install process covering lightbar primer application...

 

[dalton108]

It separated from the light bar, not the glass. Tesla added a bunch of notes to the install process covering lightbar primer application...

Correct.

 

[Diveflyfish]

Correct.

Then it sounds like a contamination issue while
Assembling the bar…….. do you all have any photos of the failed interface? I would love to see microscopic images. That may help to
understand what happened.
Cheers

 

[mongo]

Then it sounds like a contamination issue while
Assembling the bar…….. do you all have any photos of the failed interface? I would love to see microscopic images. That may help to
understand what happened.
Cheers

Posts #6 and #14...

 

[Diveflyfish]

Posts #6 and #14...

Insufficient surface area of adhesive, also very suspect is lack of adequate surface decontamination of light bar itself or a failure of the coating on the bar. Micro mechanical surface prep increases surface area dramatically and can make all the difference in the world……. So it’s not the adhesive as the problem…… it’s a substrate prep issue, as well as quantitative distribution of said adhesive surface area used as key for failure…..

 

[dalton108]

Then it sounds like a contamination issue while
Assembling the bar…….. do you all have any photos of the failed interface? I would love to see microscopic images. That may help to
understand what happened.
Cheers

I posted an image of my separation above.

https://www.cybertruckownersclub.co...-while-driving-on-highway.41921/post-30574733

To my knowledge every single one has had the adhesive separate from the bottom of the light bar; not from the glass. No idea why they wouldn’t rough it up or something, but I know that in my case they did not. No texture on that thing at all.

 

[Diveflyfish]

I posted an image of my separation above. To my knowledge every single one has had the adhesive separate from the bottom of the light bar. No idea why they wouldn’t rough it up or something, but I know that in my case they did not. No texture on that thing at all.

https://www.cybertruckownersclub.co...-while-driving-on-highway.41921/post-30574733

For sure the surface would benefit from roughening as well as optimal solvent pre-clean…….. anyone who has built a composite aircraft or worked with fiberglass knows how important that is! It’s perhaps just an oversight or inappropriate solvent preclean as prep? Dunno. Ultimately even in dentistry, the largest issue for bond stress is variance in office e of thermal expansion, and if that is ignored, things fail. If prep and surfaces are not optimally prepared failure is guaranteed. If one could figure out the confident of thermal expansion for all materials at that interface, the cause will become more clear. Either it’s a failed prep issue or missed a large discrepancy in thermal expansion. Just my two cents worth.

 

[Diveflyfish]

For sure the surface would benefit from roughening as well as optimal solvent pre-clean…….. anyone who has built a composite aircraft or worked with fiberglass knows how important that is! It’s perhaps just an oversight or inappropriate solvent preclean as prep? Dunno. Ultimately even in dentistry, the largest issue for bond stress is variance in office e of thermal expansion, and if that is ignored, things fail. If prep and surfaces are not optimally prepared failure is guaranteed. If one could figure out the confident of thermal expansion for all materials at that interface, the cause will become more clear. Either it’s a failed prep issue or missed a large discrepancy in thermal expansion. Just my two cents worth.

Coefficient of thermal expansion ****** auto spell issue sorry!

 

[rrizzi7210]

Sucks this happend to you OP. Hope Tesla comes through. I got mine installed on Thursday May 8- hope they used the latest UPDATED instructions & stays on.

To those who got it installed - do you do any car washes? Ive been using touchless but am holding off for a few days before I go in with the lightbar installed.

I use both types of car washes, no issues whatsoever after seven months.

 

[mongo]

If prep and surfaces are not optimally prepared failure is guaranteed. If one could figure out the confident of thermal expansion for all materials at that interface, the cause will become more clear. Either it’s a failed prep issue or missed a large discrepancy in thermal expansion. Just my two cents worth.

With a differential expansion of 100 ppm (random plastic vs glass), the ends of the light bar would shift 0.1mm relative to the center per degree C. Warm cabin vs cold world could be 30 C or more (but windshield will be somewhere between the two). That's 3 mm of shift. The new process calls for 1.5mm spacer pads, so 2x shift versus thickness, assuming the adhesive doesn't constraint the plastic. Betaseal Express has elongation of >400% and tensile stength of 1000psi.
Sqrt(3²+1.5²) = 3.35 or an elongation of 224%, so it seems like it would work.

Coefficient of thermal expansion ****** auto spell issue sorry!

You can edit your posts, click the three dots for menu (at least mobile version).

 

[Diveflyfish]

With a differential expansion of 100 ppm (random plastic vs glass), the ends of the light bar would shift 0.1mm relative to the center per degree C. Warm cabin vs cold world could be 30 C or more (but windshield will be somewhere between the two). That's 3 mm of shift. The new process calls for 1.5mm spacer pads, so 2x shift versus thickness, assuming the adhesive doesn't constraint the plastic. Betaseal Express has elongation of >400% and tensile stength of 1000psi.
Sqrt(3²+1.5²) = 3.35 or an elongation of 224%, so it seems like it would work.


You can edit your posts, click the three dots for menu (at least mobile version).

Thank you !

 

[Nutron]

If EVER they get one here in florida to complete my FD Series (out of stock) I will keep a close eyein this. Thanks

 

[cyberstocker]

And the Panic ensues

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